1. Field of the Invention
This invention relates to a process for preparing lymphokine activated killer (LAK) cells and to a method of adoptive transfer therapy using the cells so prepared.
2. References
Thiele, et al., Journal of Immunology 134, 786-793 (1985), disclose that L-leucine methyl ester (Leu-OMe) causes lysosomal disruption and death of human monocytes. In addition, L-leucine methyl ester removed natural killer cell (NK) activity from human peripheral mononuclear cells. The authors disclose that a brief preincubation of human peripheral mononuclear cells with Leu-OMe (1 to 5 mM) caused irreversible loss of NK function as assessed by lysis of K562 target cells. They report that a variety of other amino acid methyl esters, including L-glutamic dimethyl ester, L-valine methyl ester, and L-isoleucine methyl ester caused reversible inhibition of NK activity but did not cause irreversible loss of all NK function. Even when much higher concentrations of the other various amino acid methyl esters were used, only L-glutamic dimethyl ester was found to be able to effect NK function irreversibly. Only Leu-OMe and L-glutamic dimethyl ester were found to be toxic towards human monocytes. The authors do not mention phenylalanine methyl ester.
Lanier, et al., Journal of Immunology 134, 794-801 (1985), disclose that highly purified recombiant interleukin-2 markedly augments the natural killer cell-mediated cytotoxicity of peripheral blood lymphocytes. The authors report that all recombinant interleukin-2 responsive cytotoxic NK cells were found within the subset of lymphocytes expressing the Leu 11 marker, an antigen associated with the Fc-IgG receptor on human NK cells. Activation of Leu 11.sup.+ NK cells resulted from a direct effect of recombinant interleukin 2 on these cells and neither required nor was amplified by the presence of T lymphocytes.
Rayner, et al. Cancer 55, 1327-1333 (1985), disclose that lymphokine-activated killer (LAK) cells can be generated by incubating fresh peripheral blood lymphocytes in interleukin-2. The authors disclose that LAK cells kill fresh autologous and allogeneic human tumor cells in vitro. The LAK cells can be generated from preipheral blood lymphocytes of normal individuals and tumor-bearing patients. They report that pure, recombinant interleukin-2 generates LAK cells capable of killing a wide variety of tumors including sarcomas and cancers of the colon, pancrease, adrenal gland, and esophagus. The authors state that the LAK system is distinct from the natural and classic cytolytic T-lymphoid systems. LAK cells, generated in recombinant interleukin-2, can lyse NK-resistant tumor cells. They report that the use of LAK cells, possibly with the systemic administration of rIL-2, represents a promising future approach to the immunotherapy of human cancer.
Shau, et al., Journal of Immunology 134, 1136-1141 (1985), disclose that human natural killer cell activity in peripheral blood lymphocytes is totally inhibited by pretreatment of the effector cells with a lysosomotropic agent, L-leucine methyl ester. The authors further report that natural killer activity can be regenerated in the NK cell-depleted peripheral blood lymphocyte population by incubation with IL-2 or by mixed lymphocyte cultures.
Thiele, et al., Journal of Immunology 131, 2282-2290 (1983), disclose the use of the lysosomotropic compound L-leucine methyl ester to delineate the phenotype of the accessory cells involved in human B and T cell activation in vitro. They report that L-leucine methyl ester (Leu-OMe) caused lysosomal disruption and selective death of human monocytes and that Leu-OMe preincubation abolishes mitogen-induced lymphocyte responses. Responsiveness was completely restored by coculture with a monocyte enriched glass adherent cell population.
Thiele, et al., Proc. Natl. Acad. Sci. USA 82, 2468-2472 (1985), disclose that when mononuclear phagocytes or polymorphonuclear leukocytes were incubated with Leu-OMe, there is formed L-leucyl-L-leucine methyl ester (Leu-Leu-OMe), which elimianted all NK function from mixed lymphocyte populations. They report that this effect did not require the presence of mononuclear phagocytes or polymorphonuclear leukocytes. When amino acids with nonpolar R groups were substituted for leucine in either position, the resulting dipeptide methyl ester was generally found to display at least some degree of NK toxicity. The authors further reported that previous experiments had shown that compounds such as valine methyl ester and phenylalanine methyl ester or combinations thereof did not delete NK function from human peripheral blood mononuclear cells.
Mangan, et al., Infection and Immunity 46, 332-339 (1984), disclose that removal of monocytes from unfractionated cells by several means, including the use of Leu-OMe, resulted in a population of cells responsive to Fusobacterium nucleatum induced polyclonal B-lymphocyte activation (PBA) and unresponsive to PBA induced by pokeweed mitogen.
Meineke, et al., Fed Proc 44, 1688 (1985), disclose that when peripheral blood mononuclear cells were depleted to 4% monocytes by adherence to plastic, or nylon wool or by treatment with L-leucine methyl ester, enhanced LAK activation and reduced cell concentration dependency was seen after removal of the monocytes by each technique.
Rosenberg, et al., The New England Journal of Medicine 313, 1485-1492 (1985), disclose preliminary results of the systemic administration of autologous lymphokine-activated killer cells and recombinant IL-2 to patients with advanced cancer. They treated 25 patients with metastatic cancer in whom standard therapy had failed. Objective regression of cancer (more than 50 percent of volume) was observed in 11 of the 25 patients. Complete tumor regression occurred in one patient with metastatic melanoma and had been sustained for up to 10 months after therapy.
In the effort to further investigate and refined LAK cells and rIL-2 as an adoptive immmunotherapy for cancer, improvements which enhance the activity of the LAK cells, or which allow activation at a higher concentration of cells or otherwise offer increased attractiveness of the therapy are most desirable.